Automatic brake for power-actuated elevators.



UNIT D STATES PATENT o FroE.

'rHADpEUs W. .HEERMANS, or ET'VANSTON, ILLINOIS.

AUTOMATIC BRAKE FCR POWER- -AGTUATED ELEVATORS.

Specification of Letters Patent.

Patented arch 1-3, 1906.

Application filedJanuary 16, 1905. Serial No. 241,366-

To all whom it may concern:

Be it known that I, THADDEUS W. HEER- MANS, a citizen of the United States, residing at'Evanston, in'the county of'Oook and State of Illinois, have invented certain new and useful Improvements in Automatic Brakes for Power-Actuated Elevators; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of'reference marked thereon, which form a part of this specification, I e a This inventionvrelates' to a novel braking apparatus for elevator-cars; and the inventron consists in the matters hereinafter set forth, and more particularly pointed out 1n the appended clanns.

. acting upon the motor-shaft, as the armature- 1 shaft of an electric motor, the brake servm not only to counteract the momentum am arrest the movement of the motor-shaft, but

' "also to arrest the movement of the elevatorcar. It is highl y desirable in a successful elevator apparatus that'the braking mechanism be so constructed as to bring the elevatorplatform to a state of rest and hold the same at the level of the floors from which or upon which .the car is to be loaded or unloaded. Inasmuch as theload of an "elevator-car 'con- .stantly varies, it is extremelydiflicult "in practice to operate the motor braking apparatus in a manner to bring the car to a gentle stop or state of rest within a fixed distance from the time of application of the braking power and hold the car at such level. This is due to the fact that it is impracticable tosoad j ust the motorybrake to existing conditions as to arrest the umtor-shaft amltherethrough the car within prescribed limits, there being 'no mamtamablc relation between such brak It is eusing action and the varying loads; tomary to slightly overweight the car with the counterweight, and the unreliability in stopping the carat a predetermined level is liable to occur when the caris moving in eitherdirection. In other words, when the car ismoving upwardlyslightly loaded or downwardly heavily loaded it is inclined to overrun or pass the level at which it is intended that it should stop, to the same extent that the car is inclined to reverse its direction of motion after it has been arrested when moving u wardly heavily loaded or moving downwar ly lightly loaded. To overcome these defects, a braking apparatus supplementary to the motor 'brakin apparatus isemployed, and itis constructec to utilize the load of the car and its contents or the over load of the counterweight when the motor is arrested or slowed down by its brake for bringinglplhe car to rest or reducing its speed. Any or ary or preferred brake may be aplied for arresting the momentum and bringmg to rest the motor-shaft. The braking a paratus for the car relieves the motor-bra e from the work of arresting the car, so that the only work required of the motor-brake is to arrest its own momentum. Inasmuch as this factor is a constant one, the motor-shaft isarrested within the-same periods under all conditions of loads. My im roved braking a paratus is constructed to e operated by t 1e overload in either direction, so that the holding of the car when arrested is not thrown on themotor-brake. The action of ;the car-brake is, however, 1nodified by that of the motor-brake in the sense that its response is dependent upon the character of the action of the motor-brake. If the motor be arrested suddenly by its brake, the action of the car-brake is rompt to arrest the car,

while agradual re uction of the speed of the motor results in a correspondingly gradual reduction of the speed of the car. The action of my improved brake is such also that its retarding influence is felt whenever there is atendency of the load to drive the motor-shaft or other actuating .power either when the motor is in operation or at other times that is .to say, whenever there is an overload in either direction of movement of, the car the tendency of this overload to drive the actuating power is absorbed by the braking apparatus erein shown and'described, and suc brak-l ingdevice acts within a practically-fixed dis tance to arrest the movement of the car.

Said braking apparatus is so associated-withthe driving connections between the motor and car that it constitutes when the car is run ning at a normal load a part of the driving connection and only functions as a braking apparatus when an overload exists inone direetion or other of the car.

Lowe in the drawings, Figure l illusiical elevator apparatus including car, and countr weight to which my invention may be or I d. 2 is a Q'itudinel sectional vien my improved -ing device showing the he in meshing 'th the drum gear-wh Figs. 3, 4, F e transverse sections taken on lines l l, and 5 5 of Fig. 2. s shown in the drawings, Fig. l, A desigs a1: elevator-car; A, the shaft therefor; the motorlor driving the car, herein iov 'oi'nprising an electric motor; 0, a un: wl driven by said motor through lie niedn oi suitable gearing, and D a 'ounterwcig ht, Said car and counterweight connected with the drum through the ans of cahl ble guirn Cr and directing sheaves in a iiliar inrinr. The drum C is shown as located at foot of the shaft A, and the is const rweighted through the drum in a iar and l? (lGSlgllhU-B diagrammatically the device for the motor-shaft B controller for the motor, both of EIlP }are operated in any suitable t in c r. I

p g a worm-gear which is Wnh and drives the drum C in a c on. Said gear is inclosed in a 1. .lt lS rotated through the t E and meshes with the The said worm-screw nut, it being interiorly ,J 'age the screw-threaded arma tu rc-slial't, whereby v w may by relative rotation of w and the armatureeshatt be e of said armature-shaft As 11, both the worm-screw and art are provided with lettduinded srld worm-screw and a portion are iclosed by a suitis nmde integral with as mwn, and the adapted to be submerged ti easing. it will be obr patron of the screw- J therci n tends to shift se of the shaft, its direc "Jill und the direcivlcchanism is is with such end i, G and serves s a d, which are trained over is mounted on and is rotated by or other locking mechanism, which operates to lock the worm-screw from rotation, and thereby arrest the drum and the car from movement in either direction. Said mechanism is made as follows: B B designate collars which are non-rotatively fixed to the armature-shaft by pins b b and are located one at each end of the screw-threaded part of said shaft. H H designate cam or wed e rings looselysurroun ding the arm ature-sha 't, one between each of the collars B and the adjacent end of the worm-screw G. Said rings serve also as thrust-rings and are *brought into use to lock the worm-screw to the shaft Said ca1n-rings are provided at their inner ends with radial flanges 71-, and cxtending inwardly from the outer nuirgins of said flanges are tubular extensions or sleeves H. Said sleeves H surround and receive smaller tubular extensions or sleeves, as G, extending outwardly from the ends of the worm-screw. The outer ends of said rin s H are reduced and bear against the inner l' flC-GS of the fixed collars B on the shaft. Interposed between the flanged ends of said camrings and the adjacent ends of said wormscrew- G and contained in the annular spaces between the sleeves G H are a plurality of annular friction-plates g' kg. The plates 7L2 are interlocked with the sleeves H, whereby they rotate about the armatureshatt when the rings H rotate, while the plates 9 are similarly interlocked with the sleeves g of the worm-screw and rotate with said wormscrew. As herein shown, said frictiomplates are provided with lugs h g, which enter suitable longitudinal slots in said sleeves or tubular telescopic extensions of the rings and worm-screw. The lugs g of the plates g extend inwardly from the inner margins thereof and enter oppositely-located slots in the sleeves G of the screw G, while the lugs h of the alternate plates 72 extend outwardly from the outer margins thereof and enter oppositcly-disposed slots in the sleeves or cxten sions H of the cam-rings H l I designate a plurality of cylindric rollers which are located in annular chambers i hes tween the peripheries of the rings H, just iii roar of the flanged parts 7r thereof and surrounding inner-facing cylindric bearingsur faces j, Fig. 3, formed in stationary annular parts J, that have screw-tlnradcd engagement with the ends of a sleeve J, contained within the casing c. The sleeve and end screw-tiireaded parts are1'i n-rotative in said casing, as shown in Fig. 2. Such annular parts I of thecasing are provided with inwardl x-extending flanges j, Fig. 2, parallel with the flanges 72- of the rings H, the two lluuy cs constituting the end walls of the spaces or chambers before relr .ylindrir rollers l are sepa- 1st. said amiular chambers by inc-ins of short came-mus Ii", extending outwardly from that the ringsH are free to rotate in the di rection toward which face the cylindric recesses 'ofthe arms without being restricted by the rollers, but are prevented from rotating in the opposing direction, inasmuch as said rollers are pinched between the camfaces of the-arms and the innercylindric surfaces yfof the bearing ch'amber; The camarms are so disposedthat one ring; H is thus leaked from rotation in one direction-and the other is locked from rotation in the opposite direction. With this construction it will be I observed that rotation of the armature-shaftv collar 13.

in the proper direction acts, through the screw-threaded connection of said shaft with the worm screw, to shift the worm -screw endwise in onedirection and to force said worm-screw tightly agalnst one group or complement of-,friction-plates g b and therethrough to force the associated cam-ring H against the adjacent collar B. When said parts are thus forced, together, the wormscrew is locked to the armature-shaft in a manner to transmit power therefrom to the worm-wheel C and drum; It will be furthermore observed that when the worm-screw is thus shifted in one directionandis locked to the armature-shaftthrough one complement of friction-plates and cam-ring it moves away from the other complement of frietion plates and ring and frees the latter fromfrictional contact Witheach otherand the associated It will be. observed also that the worm-screw is locked to the-armature-shaft through the medium of one set of washers and their associated ring H and collar B when the shaft is rotating in one direction and is locked to said shaft when the rotation.

f the latter is reversed through the medium. of the other set of washers and their associated ring II and collar B; l/Vhen, therefore, one complement of friction-platesat one end. of the Worm screw f unction's to lock the worm-screw to the shaft, the opposite complement are loose, and vice versa. 4 The cam or 'wedgc rings and rollers I cooperating with thecylindric bearing-surfaces of the parts J of the.casing cooperate with the friction.

plates 9 and k and worm-screw to. utilize the momentun'i of the load of the car orcountere weight in either direction to prevent over' running of the car and arresting it within practicable presrribml limits, and said parts also cooperate to arrest the car when either the weight of, the car or the counterweight tends to move the car beyond its landinglevel after the car has been brought to a state '01 rest. Said brakingmechanism operates 0 Only to. stop the car when the motor is arrested, but its retarding influence is felt whenever there is a tendency of the load of the car or counterweight to drive the motor in either direction. v .The operation of the braking mechanism 1 to utilize the momentum of the car to arrest the movement thereof will be understood from a consideration of the following: It is structionboth the .armattire-shaft, and the worm-screw have left-hand screw-threads.,,

first to be noted that inthe illustrated 'con- It will be furthermore observed that the noiseless ratchet mechanism (embracing the rollers I and the cooperating cam-arms) are so arranged that when the armature ormotor shaft rotates to the left and the worm-screwor nut G is locked to the through the medium of thefltft-handcom latmaturdshaft plement of friction-plates 97,lthe ring H, and

collarB, Fig. 2, the said 1' ngI'H is free to rotate with the shaft, it rotating at this time in the direction indicated by the arrow in Fig. 3. When the armature or motor shaft rotates in the opposite direction, or to the right, the worm-screw is locked to the shaft by the right-hand complement of frictionplates 9 h, ring H, and collar 13, and the ar;

rangement of the associated noiseless ratchet mechanism permits J he shaft to rotate in Q this direction. Whe lthe worm-screwis thus locked to rotate with the shaft in either direc tion, an overload tending to cause the car to I overrun its landing-level has the effect to back the worm-screw away from the active set of friction-plates without change of direction of rotation of the screw and look said screw to the shaft through the otherset of friction-phites, and inasmuch as the ratchet mechanism ad acent to the latter plates is active in this direction the worm-screw and shaft are arrested. If undelitthe same conditions the overload of theear or counterweight tends to reverse the d'tiection of'rotation of the worm-screw an'd'shaft after the latter have been arrested, the screwwill remain locked to the shaft, as before, but both. v the drum endear will be arrested by'the ratchet. mechanism adjacent to the active} friction-plates. 4 If it be assumed that the armature-shaft T 5 rotates to the left to raise the elevator-car,

the direction of movement of the screw G and gear 0- will he that indicated by thearrotvs,

and atsuch timethe worm-screw islocked to the shaft through the left-hand washers, camring, and collar. -lf now thecar is to be stopped, the armature-brake is thrown into action to arrest the rotation of the armature? shaft. Should the car he so lightly loaded that the momentum of the'counterweight tends to carry the car. heyond'itslandinglevel, the/result is that the-'gear C or other v load of the counterweight"and drives the" worm-screw or not G' mthe orig nal d1reoeal connected withthe caris driven by the tion, with the result of backing the worm from the left-hand complement of frictionrings against the right-hand complement of friction-rings and cam-ring H. the right-hand camarms and rollers are active to lock the adjacent ring H from rotation in such original direction of rotation of the worm-screw or nut, the result of thus forcing said Worm-screw against said right-hand complement of thrust-washers and cam-ring is to lock said worm-screw, and therefore arrest the gear C and the car connected therewith. When the car is again started up wardly, the worm-screw or nut is shifted to the left and locked to the shaft, as before. It is evident also that the braking action of the mechanism described manifests itself during the time the car is traveling upwardly if the car be lightly loaded and is overbalanced by its counterweight. In such case when the action of the weight tends to drive the armature such overload acts, through the endwise-shifting worm-screw and friction-washers, to momentarily arrest the car until it is overtaken and again driven ,by the armatureshaft. Such action is not sufficiently evident as to manifest itself perceptibly in the movement of the car. If, however, a heavily loaded ascending car he stopped and the load of the car afterthe car is arrested tends to drive the worm-screw and armature-shaft in a reverse direction, the worm-screw will not he released from the shaft, and inasmuch as the locking mechanisLn to wit, the asso' elated cam-arms and rollers are active in this direction the load will be held.

The action of the driving and braking mechanism on a'descending car is the reverse to that described when operating to lift the car. For instance, if the car is oven balanced by its counterweight and is descending lightly loaded, power will be exerted through the armature-shaft and worm-screw (rotating in the illustrated instance to the right) to overcome the Weight of the counterweight. When. the car is now brought to a stop, it is prevented from reversing its direction in the same manner as a heavily loaded descending car is held and as hereinabove described.that is to say, by the ratchet mechanism adjacent to the frictionplates theretofore in service. If the descend- 'lng car be heavily loaded, however, the action of the armatureshaft when reversed to lower the car is to back the worm-screw from the friction-plates theretofore in service and release the latter. This action allows the load to momentarily descend by its own weight, thereby drivmg the worm-gear relatively to the armature-shaft until it is locked by the means described. The continued motion of the armature-shaft again releases the worm-screw, so that the action of lowering the load. is that of continuously releasing the friction-plates by the motion of the motor Inasmuch as;

. in suitable hearings K K,

shaft. and the continual effort on the part of the load to overtake the armature-shaft and relock itself. "It is manifest from the foregoing that 'while the motor-brake is relieved from the work of holding the car after it has been arrested, yet the action of the motor-brake modifies that of the car-brake, and therefore cooperates with the car-brake to control the car -that is to say, the promptness with which the carbrake is brought into action to arrest the car under usual running conditions depends upon the greater or less activity with which the motor-brake is operated to control the motor and its shaft. if the motor-brake be set to bring the motor to a stop within a minimum time, the car will be arrested by its brake with corresponding promptitude. If, l1owever, the motor braking power he slowly applied, the effect of the action ol' the Yer-brake upon the car is therefore more gradual. The car is therefore under the perfect control of the conducthr at all times and without the necessity on the part of the conductor calculating the relation of the load on the car to the effect of the action of the brake mechanism.

llt will he observed that the friction-plates g 773 and rings ll constitute when the wormscrew or nutis locked to the shaft merely thrust elements interposed between the stop-collars B and the worm-screw, whereby thii wormscrew is locked to the shaft by a shearing action of the screw threads of the shaft and screw. When, however, the cam or wedge rings are locked to the casing, the friction between the washers is brake the load of the elevator-car. hen such braking action takes place, the load of the car is free or released from the armatureshaft; but such condition prevails but 1110- mentarily when the elevator is in active service. The construction described constitutes a sensitive brake and one which may always he relied upon for efficiency and prompt service.

The armature-shaftis rotatively mounted which are located atthe ends of too casing C The end of said shaft remote from the armature is reduced and is provided with a sleeve 6', non-rotative on the shaft, which sleeve has bearing in a sleeve 7c in the bearing K. The bearutilized to arrest or.

ing K is formed to provide a t ,pical form of stuffing-box I), Fig. 1, throng which the 'arrnature shaft B extends. The other hearing K extends into the casing C and is fastened therein by bolts k extending through an annular flange 7c at the end of the bearing and into the end of the casing. The same bolts fasten a cap K over the end of the hearing. The outer end of the bearing K is enlarged to constitute an annular chamber K to receive a thrust-bearing for the arrnatureshaft B, said thrust-hearmg acting ,to take the end thrust of the shaft in both directions. The thrust-bearing maybe of any suitable form and, as herein shown, is'made as follows:

B designates a collar non-rotative on the shaft within the annular enlarged phrt of the bearing K and is immovable endwise of the threet lded engagement with the outer end of the s aft an occupyinga recess in the cap K of the bearing K, Located between said collar B and said cap on one side, and a shoulder k on the other side are hardened plates k k arranged in parallel pairs and between wh" h are interposed antifrietion-rollers k con ed in suitable cages.v The, endwise thrust of the shaft in both directions is taken by the-double thrust-bearing described. The parts are so constructed as to permit the parts-of the brake and driving-gear contained within the casing C to be inserted for the most part, when being taken apart or assembled,

through the end of the casing containing the thrust-bearing when the hearing K is re moved. v

I claim as my invention I a 1. In a ower-driven elevator, the combination wit the car, its counterweight, a motor for driving the car and a brake for arresting car constructed to arrest the carby the momentum of the load acting in either direction,

2 In ap'ower-driven elevator, the combinatlon with the car, its counterwe'i ht, a mo tor for'driving the car and a brake or arresting the motor, of a braking mechanism for the car, and connection between said braking mechanism and the car and counterweight constructed to be actuated by the load .ormomentum of the car and counterweight acting in either direction to automatically bring the car to rest.

In a ower-driven elevator, the combination wit the car, its counterwei ht, a mo-. tor for driving-the car and a brake or arresting the'motor, of a braking mechanism for the car and connections between the braking mechanism and car and counterweight so constructed that said braking mechanism operates independently of the motor-brake to' arrest the car by the load or momentum of the car and counterweight acting in either direction.

4. In a ower-driven elevator, the 'combination wit the car, its counterweight, a motor for driving said; car, (gearin connecting the motor with the car an a bra efor arrest I ing the motor, of a friction braking mechanism operatively connected with the car andcounterweight and designed to be set in motion by the momentum or weight of the load i'nieither direction for arresting the car.

' 5. In a ower-driven elevator, the combination wit the car, its counterweight, a drum" to the opposite sides of which the car and counterwelght, respectively, are connected, a

reversible rotary motor-shaft geared to. the drum, and abrake for said shaft, of a braking mechanism for the car embracing in part a portion of thegearingubetween the shaft and drum and in part bra ng elements cooperating therewith in a manner to utilize the weight or momentum of the load. on the drum in either toarrest the car.

'6 In a ower-drlven elevator, the combination wit the car, its counterweight, a motor for driving said car, gearing connecting the motor with the carand counterweight embracing a screw-threaded rotativemotorshaft, a gear surrounding and having screw- -threaded engagement with said shaft, and

designed to be locked to the shaft through'rotation of said. shaft toconstitute part of the car-drivin ear mechanism and to betemporarily re eased from the shaft when the load tends to drive the shaft, and a brake for arresting the motor, of a braking mechanism for arresting the car, comprising means cooperating with said screw-threaded gear when said gear is temporarily released from the shaft-as a driving connection for locking said screw-threaded gear to arrest the car.

7 In an elevator, the combination with the car, its counterweight, a motor for driving the car, gearing connecting the motor with the car and counterweight comprising a screw-threaded, rotative motor-shaft and its bearing, a screw-threaded ear mounted on said shaft and meshing wit a coacting gear. forming part of the drivin gear, and a brake for the motor, ofmeans w ereby said screw: threaded driving-gear is locked to the shaft when the motor is driving the car, and means. whereby said gear is frictionally locked to the motor-shaft hearing when the load of 2 the car or counterweight tends to drivethe screw-threaded gear.

8. In an elevator, the combination with the car, its counterweight, a motor for driving the car, gearing connecting the motor -;with the car and counterweight embracing a screw-threaded motor-shaft and, its stationary hearing, a worm-screwsurrounding and having screw-threaded engagement with said shaft and meshing with a worm-wheel forming part of the gearing between said motor and the car and counterweight, means-whereby the worm-screWis locked to theshatt by rotation of the latter to constitute part of the driving mechanism, and a brake for said motor, of a braking mechanism cooperating with .said worm-screw, and operative'when the worm-screw is releascd lrom the motorshaftto frictionally lock the worm-screw to the'stationary' bearing of the motor-shalt:

-.9. In an elevator, the combination with the 'car, its counterweight, a motor for driv ing the car, gearing connecting the. motor with the car and. counterweight, embracing a,

screw-threaded nwtor-shaft loosely surrounding the motor-shaft at each -while permitting them to shaft in the other direction a worm-wheel meshing therewith, means for car,

and its stationary bearing, a worm-screw surrounding and having screw-threaded engagement with the shaft and meshing with a worm-wheel form- :ing part of the gearing between said motor and the car, and counterweight, means whereby the worm-screw is locked to the shaft by rotation of the latter to constitute art of the driving mechanism, and a brake fbr said motor-shaft, of a car-braking mechanism cooperating with said wormscrew, comprising two sets of eoacting frictionwashers at each end of said screw, one set carried by the worm-screw, and rings loosely surrounding the motor-shaft and carrying the other or coa cting set of washers, one ring rotating freely in one direction and the other in the other direction, and means for locking each ring from backward rotation.

10. In an elevator, the combination with the car, its counterweight, a motor for driving the car, gearing connecting the motor with the car and counterweight, embracing a screw-threaded motor-shaft and its stationary bearing, a worm-screw surrounding and having screw-threaded engagement with the shaft and meshing with a worm-wheel forming part of the gearing between said motor and the car and counterweight, means whereby the 'worm-screw-is locked to the shaft by rotation of the latter to constitute art of the car-driving mechanism, and a bra e for said motor-shaft, of a car-braking mechanism cooperating with said worm-screw, comprising coactingfriotion devices, one set being car ried by each end of the worm-screw, rings end of the screw and carrying the other coacting friction devices, and means for locking said rings from rotation in one direction rotate with the and so arranged that the rings are locked from rotation in opposite directions relatively to each other.

11. The combination with an elevator-car, its counterweight, and a driving-motor, of driving connections between the motor and car, including a screw-threaded rotative shaft, 2. worm-screw surrounding and having screw-threaded engagement with said shaft,

locking said worm-screw to the shaft when I the shaft is rotated in a direction to drive the I and means for frictionally locking said i Worm-screw from rotation independently of I the shaft when the motor of the car or eoiinj terweight on the worm-wheel acts to drive the worm-screw in either direction.

12. The combination with an elevator-en 1'. anda motor, of driving connections between the motor and car, which includes a brake mechanism comprising a screw-threaded rol l tative shaft, a worm-screw surrounding and i and braking mechanism comprising, in it mebmation with a. screwtlireadeil inotor-- at,

a worm-screw surrounding and having serewthreaded engagement with said shaft and meshing with a worm-gear constituting part of the car-driving nmchanism, and to the on posite sides of which the ear and counter weight are connected, collars fixed to said shaft, one at each end of said wornnserew, rings loosely mounted. on said shaft between said collars and worm-screw, said rings and worm-screw being provided with sleeves ontering one within the other, friction-weshers surrounding the inner one of said sleeves affixed alternately to the said sleeves, whereby alternate washers of each set have frietional engagement with each other, and means whereliy said rings are locked from rotation in one direction and are free to rotate with the shaft in the other direction.

14. The combination with an i"l(5 .':tit1i-(1lI, its counterweight, and its motor, of a com bined driving and braking mcii-hanisni the-rt for, comprising a rotativc screwthreaded shaft, a worm-scrcw surrounding and having screw-threaded engagement with the shaft, and meshing with a worm-gear constituting part of the.elevator-driving mechanism and to the opposite sides of \chich gear the car and counterweight are connected, collars on the shaft at each end of the \YOIIHN'HWY,

rings loosely mounted on said shaft bet ween said collars and scrcw-threaded gear, provided with a plurality of arms havin; one side thereof wedge or "am fac s and the other side rounded recesses, rollers int erposed between said arms and oeenoving chambers surrounding said rings, said rin and scrcw-threaded gear being provided with sleeves which fit one within the other. and friction-washers arranged between and lied in alternation by said slee es.

in testimony that 1 claim the ftlllgfllif i es hilt] j my invention 1 allix inysigi'iatnre. in 'ii'ei-e iee of two witnesses, this 6th day of daniiarv, l). 1905. 

